I work for a web hosting company and we are looking for some SMTP software with Active Directory integration. Really it just comes down to something our customers can use easily with the SMTP service authenticating against their web process identity. We're running IIS 7 so we'd like to avoid the IIS 6 SMTP, which really isn't robust enough to begin anyways.

Our requirements really seem simple, but we keep hitting barriers with the software we are evaluating:

We can lock it down with active directory to prevent spammers from signing up

Ideally runs on Windows, but we're plenty comfortable with *nix based systems

Good logging support so we can track who might be abusing the system

The ability to throttle the amount of mail to prevent people from spamming

Ideally would be able to set to run in a HA scenario

All the solutions that I keep running into seem like overkill, or don't have support for active directory. Any suggestions?

So, "web process identity" just means their Active Directory account? If so, pretty much any SMTP server that can do LDAP authentication can do what you want, from an authentication perspective.
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Evan AndersonJun 19 '09 at 3:38

Yeah, we're just creating them a user name like "Website59_Identity" and marking their app pool to run under that identity. And honestly I thought just about any SMTP server could do this but it's a giant mess in windows land. I read Matt's article about Postfix and I'm gonna send it along to some of the other engineers and see what they think. I'm just a lowly web developer who thinks our current solution is a joke, so I was curious to get the outside's world opinion.
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Phil ScottJun 19 '09 at 3:43